Automatic air-supply valve for ice pans



July 9, 1929. l. cowLEs A AUTOIATIC AIR SQPPLY VALV FOR ICE PANS FiledAug. 12, 1925 2 Sheets-Sheet l Ju ly 9, 1929. cowLEs AUTOHATI AIR SUPPLYVALVE FOR ICE PANS Filed Aug. l2,` 1925 2 Sheets-Sheet l 2 mi M IIIHPatented July 9, 1929. -f

UNITED STATES PATENT OFFICE.

IRVING COWLES, OF CHICAGO, ILLINOIS, ASSIGNOR TO UNION BANK OF CHICAGO,OF CHICAGO, ILLINOISUA CORPORATION OF ILLINOIS.

AUTOMATIC AIR-SUPPLY VALVE FOR ICE PANS.

Application filed August 12, 1925. Serial No. 49,865.

This invention relates to improvements in Vair supply valves forartificial ice making plants to feed air under pressure into thewater-freezing pans for the purpose of maintaining the contained waterin circulation during freezing thereof to thereby pre vent the formationof the core or pocket, due to concentration of the hard salts, in thetop of the cake of ice and also to prevent format-ion of so-calledwhiteice, the main object of the invention being to provide an air feed valvewhich will insure constant supply of air up to the time that the wateris solidly frozen throughout.

In artificial ice plants, air under pressure is supplied to each of thewater pans through a. metal tube depending into the same to a pointcontiguous to the bottom thereof, said metal tubes being detachablyconnected, by means of ieXible rubber tubes, with the air supply pipesdisposed above the pans. The air supply to each pan is now generallycontrolled by a pet-cock and great waste of compressed air thus resultsor, Where fine adjustments are effected to avoid such waste, it is notinfrequent that too little air is fed to prevent clogging of thedischarge end of the metal tube by forma-tion of ice therein. Constantwat-ch and inspection is necessary to prevent the interruption andproper control of the air-supply to the numerous pans of every plant andeven with these precautions, a fairly large percentage of white ice isproduced and great Waste of compressed air occasioned.

The objects of my present invention are:

First. To provide an air supplyr valve for each pan which will initiallyregulate and control the flow of air into each pan to main.

tain uniformit and prevent waste by feeding just enoug air to maintainthe required water-circulation- Second. To provide an air supply valvewhich, upon choking of the tube by formation of ice in the discharge endthereof, will Y automatically and suddenly occasion the supply to thetube of a large volume of air under the pressure maintained in the airsupply system, to thereby effect ejection of the ice plug formed in thedischarge end of the tube and thereupon return to initial position tosupply the continuous How of the smaller volume of air.

Third. To provide a valve of the character aforesaid which may be easilyadjusted to supplythe minimum air current necessitated by Waterconditions and which, furthermore, may be easily and quickly adjusted tosupply a larger volume of air during any period desired by eliminatingthe automatic operation defined in the preceding paragraph or toaccommodate the valve to a lowpressure supply system.

Fourth. To provide a valve of the character aforesaid, which will beself-cleaning.

Fifth. To provide a valve possessing the several advantages aforesaid,the several component parts of which may be easily and cheaply producedby automatic screw-machines or the like, supplemented by drillpresswork, and which is small and compact.

The preferred embodiment of the invention is shown in the accompanyingdrawings, in which: I

Fig. 1 is a central longitudinal section of a valve constructed inaccordance with the invention.

Fig. 2 is a view similar to Fig. 1 showing a member of the valve inposition to pass a larger volume of air and rendering the samepractically non-automatic.

Fig. 3 is a detail perspective view of a piston valve constitutingan'element of the structure.

Figs. 4 and 5 are perspective sectional views of two parts of the valvehousing` Figs. 6 and 7 are views similar to Figs. 1 and 2, respectively,of a modified form of construction of an air supply valve which isnon-automatic. A Y

Fig. 8 is a transverse section on sf-s of Fig. 6.`

Fig. 9 is a detail perspective section of a the line valve element ofthe structure of Figs. 6

and 7.

Fig. 10 is a perspective section of an adjusting velement employed.

Fig. 11 is a transverse section on the line n iief Fig. e.

Fig. 12 is a central longitudinal section of still another and verysimple embodir ment of the invention.

The valve comprises the housing element 1,v preferably of externalpolygonal form, such as heXagon, which is provided fat one end with anexternally threaded, hollow axial stein 2. Which is adapted to enter thethreaded openings ina compressed-air supply pipe, not shown. Theotherend of said housing element 1 is open and internally threaded to receivethe externally threaded middle portion of a housing and valve-carryingelement 3. The latter terminates at its upper end in an externallythreaded annular flange 4 bordering a central cylindrical bore 5 whichextends intoV but not through the body or middle portion 3, the flange 4being of considerably smaller diameter than said middle portion. Thelatter is providedat its lower end with an externally smooth andinternally threaded cylindrical flange 6, both said flanges beingconcentric with said middle or body portion 3.

Mounted within the bore 5 is a helical compression spring 7 which servesto normally maintain the piston 8 equipped with the cup-washer 9, at theouter or upper limit of its movement. A' needle valve 10 is looselyassociated with said piston for reciprocation ithereby, the same havingball and socket joint connection with the piston. Said needle valve v10comprises a middle, cylindrical portion presenting a tapered surface 11at its upper end and terminating-in a small, 'cylindrical projection- 12which extends Y through the air intake opening of the adjustable element13 having threaded engagement with the cap 14 which is mounted on theflange 4 and presents an internal annular shoulder 15 seating on theupper end of said the flange 6 through the opening or passage 18. At theinner end of the bore of lthe stem 2 is the valve seat 19 on which theconical upper end of the cap 14 is adapted to seat, to thereby compelall air entering the said bore to pass through the cap 14 land chamber16.

The bore 5 communicates at its inner end with atmosphere through theopenings 2O and 21.

Connection between the bore of flange 6 and the lower end of an ice panis effected through the central bore 22 of the nozzle 23 to which theflexible hose 24 is adapted to be attached in any suitable manner, saidhose being also attached to the metal tube 25, depending into the icepan. Said nozzle constitutes the lower terminal element of the kmember26 provided with the `externally i threaded nipple 27 engaging intheflange 6.V Said member 26 is provided with the an- `nular hollowflange 28 on the bottom of r"which the helical compression spring 29seats, said spring 29 bearing upon a metal washer 30 which, in turn,bears upon the leather or similar flexible cup-washer 31 slidable uponthe flange 6 and bearing upon the lower end of the housing element 1 tothereby seal the chamber 16 against escape of air through the threadsassociating the elements 1 and 3.

The member 13 includes the cylindrical flange bordering the central airintake opening therein, said cylindrical portion projecting through andsnugly fitting the central opening in the upper end of the cap 14. Belowsaid cylindrical portion, the member 13 presents a conical surfaceopposing the similar surface 11 of the valve 10 and spaced from thelatter a distance sufficient to readily permit passage of all airentering the central opening of said member around the projection 12.The last mentioned space determines the maximum air feed to the panswhen the element 13 is at the upper limit of its movement relatively tothe cap 14 and the conical upper end of the latter is seated. Byadjusting the position of said member 13 relatively to the cap 14 in thedirection of the piston 8, the space between the conical surface 11 ofthe valve 10 and the opposed similar surface of the element 13, may becontracted tolimit the volume of air to less than the capacity of saidcentral air-intake opening, as will be obvious. The member 13 isprovided with diametrically opposed recesses 17 in its inner end foreiigagement with a screw-driver for its adjustment, the latter beingusually permanent.

The operation of the above described construction is as follows Assumingthat the air pressure maintained in the air supply pipe with which thestem 2 connects, is `fifteen pounds per square inch, then the spring 7must be of such strength as to maintain the needle valve at the upperlimit of its movement against the action of said air pressure, it beingpreferable that the said valve 10 be not seated to seal the opening inthe member 13 though this might be done. YThe spring 7 may be adjustedto be normally slightly compressed by the air pressure on the-needlevalve 10 while maintaining the latter in such position as to limitthenormal flow of air to the desired minimum. The loose association of saidneedle valve with the Apiston 8 permits vibration Vof the same by theflowing air to thereby maintain the air intake opening free Vofcorrosion and of obstruction other than is vpan into 'which the tube 25depends. VConsequently, the piston 8 can be actuated against the springl7 only to the extent above indicated.

If an ice-plug should form in the discharge end of the tube 25, as notinfrequently happens, and the flow of air be thus badly impeded orwholly interrupted, then, obviously, the pressure within the chamber 16and cap 14 will instantly increase to the point (not above fifteenpounds) at which the flow of air from the stem 2 continues. Such aniceplug is rarely initially of more than film-like thickness butincreases rapidly unless promptly broken. The very rapid accumulation ofpressure in the pipe will cause the ice-plug to be wholly or partiallyblown out of the end of said pipe.

The accumulation of higher pressure in I the chamber 16 and cap 14, dueto obstruction as in the next preceding paragraph described, willobviously act upon the piston 8 to force the same downwardly against theaction of the spring 7 and thereby effect an opening movement of theneedle valve l() to an extent to completely withdraw the projection 12from the intake opening and thus promote more rapid and, in fact, almostinstantaneous building up of pressure in the pipe 25 tothe point up tothe maximum, above stated, necessary to break up or eject the ice-plugbefore the latter can be built up to apoint capable of resisting themaximum pressure.

Immediately following the breaking up or ejection ofthe ice-plug,release of pressure, in excess of the hydrostatic head of the water,takes place in pipe 25, this being evidenced by a puff of the trappedair and instant return of the piston 8 and the needle valve 10 to normalposition. This reciprocatory movement of' the valve 10 causes theprojection 12 to further cleanse the air-intake opening.

If, for example, conditions should be such that it became advisable tofeed a larger volume of air to the pans for al time, or, by reason ofaccident to the high pressure compressor, a low pressure source ofsupply should have to be substituted, the member' 3 may be very slightlyrotated relatively to the housing 1 to unseat the cap 14 and permit theair to by-pass the interior of the latter', thereby partially orcompletely eliminating automatic operation of the valve 10. Thefrictional resistance to relative rotation of the housing 1 and member 3afforded by the spring 29 and cup-washer 31 will serve to maintain thesame firmly in any relative positions to which they are turned. Thismanual operation may also be resorted to at intervals for the purpose ofblowing out solids finding their way into the several chambers andpassages other than the interior of the cap 14.

For purposes of ready identification, the needle valve 10 may beregarded as the main or automat-ic valve of the structure, and the cap14 as an Vauxiliary or manually operable valve.

It will also be noted that the device includes the rubber tube 24connecting the valve casing with the metal tube 25 projecting into thepan and constituting, at its lower end, the discharge point for the air.

The rubber tube 24 permits the operator to momentarily shut off' thesupply to the tube 25 and thus to build up pressure in the valve casingfor the purpose of fully opening the intake port by reason of responseof the piston to the pressure to thereby insure the removal ofobstructions from thel intake port. To do this it is only necessary topinch and collapse the tube 24 between its ends and so hold it for a fewseconds. This operation also affords a means for ascertaining thecondition in the pan so far as the extent to which the water therein isfrozen since the resistance to pinching and collapsing of the rubbertube clearly indicates whether the air. therein is under the normal lowpressure or the maximum pressure. The rubber tube 24,V when operated asabove pointed out, constitutes the equivalent of' a valve normallymaintained open by a spring.

The rubber tube 24 may be of such thickness as to expand under theinfluence of the maximum pressure to a degree to release it fromengagement with the tube 25 as the maximum pressure is developed thereinonly when the ice cake is practically completely formed so thatdisconnection of the rubber tube from the tube 25 will indicate to theoperator that no further supply of air is required. The slush ice firstobstructing the lower end of the tube 25 is removed by pressur'esusually far below the maximums and when the latter fails to effect suchremoval it is because freezing has progressed substantially tocompletion.

In some of the smaller plants, where a single operator or watcher' caneasily make the rounds of all the pans wherein the ice cakes areaproaching finished condition, it being at this time that the ice-plugsare most likely to develop in the discharge ends of the tubes 25, andhas plenty of spare time to manually remove such plugs, thenon-automatic type of valve shown in Figs. 6 to 11 will answerrequirements. As this Vstructure includes a main valve and anl auxiliaryvalve, it may be regarded as another embodiment of the invention in sofar as the latter is not defined in the appended claims as automatic tothe extent above described.

This structure includes the housing element 1 and its stem 2, the valveseat 33 at the inner end of the bore of' the latter upon which the upperend of the element 34 seats, the latter constituting a part of auxiliaryor manually operable valve element 35. The

Y Vthe latter.

latter is integral with the nozzle 36, to which the rubber tube 24connected with the air discharge or feed-pipe 25 is adapted to beattached, and is externally threaded between its ends to engage theinternal threads in the lower part of the housing 1. lts upper endportion 37 is of smaller diameter than the interior of the housing 1 andis externally threaded to receive the said member or element 34 which isinternally threaded at its lower end. The extreme upper end portion 38of said member 35 is externally conical and presents a thin wall ofductile metal bordering the intake end of its central bore 39. Themember 34 has a central opening into which the said thin wall projectsand which it hugs, so that, upon a downward adjustment of said member34,

the said thin ductile wall will beV contract-1 ed annularly to partiallychoke the intake end of said bore 39, thereby effecting a per manentadjustment of the latter to control the volume of air capable of beingpassed therethrough. This bore is further partially choked by the pin 40which has its head 41 loosely engaged in a countersunk portion 42 at theintake end of the stem 2, said portion 42 being covered by a screen 43which is held in place between the upper end of the conical portion ofsaid 'counter-bore and overturned or crimped edge of the wall of thestem above The pin 40 is thus free to swing l and rotate relatively tothe stem 2 to thereby maintain the intake end of the bore 39 clear ofobstruction.

The bore 39 communicates with the annular chamber 33L around the member34 through the openings 44 so that, when said member 34 is unseated, theair Awill pass mainly from said stem 2 through the chamber 33a andopenings 44 into the unchoked portion of the bore 39.

Between the nozzle 36 and thefirst mentioned threads of the member 35,the latter is hexagonal and rof larger diameter, as shown at 45, therebeing an annular groove between the ends of said hexagonal portion intowhich a split wire ring 46 is sprung to form a stop. A cup element 47having a hexagonal opening 48 in its bottom which receives the upperhexagonal portion and rests upon the stop 46, is disposed to receive thelower cylindrical portion 49, of the housing 1, said portion 49 being,in effect, an annular flange at the lower end of said housing. Withinthe latter there is mounted a leather washer' 50 and a metal washer 51against which the upper end of the compression spring 52 bears, thelatter being substantially the same external diameter as the longerdia-meter of the hexagonal portion 45 and seating on the upper end ofthe latter to thereby confine the bottom of the cup 47 between saidflange and said spring. Said cup is externally knurled and constitutes ameans for j digitally rotating the member 35 against the resistanceafforded by the spring 52 and washer 50, the purpose of thelast-mentioned elements being to hold the members 1 and 35 in anyrelative position to which they may be adjusted to thus control thevolume of compressed air fed to the tube 25.

In use, the member 34 is normally seated to thus compel all air to passinto the bore 39 around the pin 40, the said bore having been previouslychoked by means of the member 34 to the extent demanded by theconditions incident to the particular place of installation. Theoperator, in making rounds at intervals, can readily rotate each of thecup elements 47 to momentarily unseat the member 34 and thus permit orcause atemporary strong blast of air to be projected from the tube 25 toclear ythe latter, this operation being necessary only when the cakes ofice are nearing completion and being frequent at this period. Thisoperation also serves to effect a relative longitudinal movement betweenthe pin 40 and the portion of t-he bore surrounding the same and thuskeeps the latter free of obstruction.

lf the plant uses only a low-pressure blower to supply the air, theauxiliary valve may be adjusted to a normal position for a steady supplyof air and the rim of the cup 47 andthe flange 49 marked to indicatethis normal position, a` further downward adjustment of the member 35being eected at intervals to increase the volume of the air supply forpurposes above set forth.

The member 34 is preferably hexagonal externally at its upper endportion to aecommodate a wrench.

All' of the several parts of the respective embodiments illustratedandjdescribed are designed for production by automatic screw machinessupplemented by drill-press and punch-press workso that they may be mosteconomically supplied to the consumer.

It will be observed that both embodiments of the invention shown anddescribed, present the feature of self-cleansing by a vibratory motionof the free end vportion of the valve under the influence. of airflowing through the structure, the automatic valve possessing thefurther advantage of a reciprocatory motion resulting from increase inback-pressure due to clogging of the discharge portion of the duct. oftravel of the air or other fluid may be reversed in the case .ofeithervof the embodiments shown and described without in any wayaffecting theV self-cleaning functions thereof. In case of reversal offlow of fluid through the structure of Figs. 1 to 5 inclusive, the areaof the lateral opening 32 in the cap 14 should be so proportioned to thearea of the valve controlled opening of the latter as to insure anormally lower pressure The direction y Within said cap than ispresented by the source from' which the air or other fluid is receivedso that, upon clogging of the valve controlled opening (as distinguishedfrom choking), or upon clogging of' the passage into which the air orfluid is discharged, the increase in pressure within said cap will besuliicient to actuate the piston against the action of its spring tothereby completely free the discharge port or passage, either by theblowing out due to increased volume and pressure of air or fluid, or tolet pass the clogging or obstructing matter which may have collectedaround the portion of the valve projecting into the discharge port ofthe cap. y

Fig. 12 illustrates an embodiment of the invention wherein the casing 1is omitted and connection between the stem 53, constituting the intakeend of the device, and the interior of the cap 14, (which is, in thiscase devoid of the lateral opening 32) is effected by means of the smallpassage 54 in the wall of the cylinder, which connects with the lateralpassage 55 connecting with the bore of the stem, the bore or passage 54being so proportioned to the normal area of the outlet port whenpartially choked, as to prevent the nor-malfluid pressure in the capfrom reaching a point in excess of, for example, one-half or one-quarterthe pressure in the bore of the stem 53. The free space around the freeend of the valve being much narrower than the diameter of the passage 54solids capable of passing through the latter may obviously beaccumulated around the discharge port until the vlatteris clogged to theextent of causing such an increase in pressure within the cap as willactuate the piston to withdraw the valve entirely from the dischargeport and thus permit the accumulated matter to be blown out. The springmust necessarily exert a pressure on or resistance to movement of thepiston properly proportioned to theV relative areas of the passage 54and exhaust port to permit the piston to respond to the increase inpressure resulting from cloggingof the exhaust port.

A structure such as is illustrated in Fig. 12 is well adapted for waterdischarge nozzles'lfor airI washing apparatus and possibly also, forcertain types of high pressure gas feed nozzles or burners wherein acontinuous feed of gas is very essential and automatic cleaning andclearing of discharge port is highly desirable.

VllVhile embodiments shown are described only with reference .to use inice-making plants, it will be obvious, of course, that they may beYotherwise used in the industries either in the identical formsillustrated or modified to particularly adapt them to other uses,without departing from the invention as defined in the appended claims.

I claim as my invention:

1. An air 'feed' device for ice plants including a valve-casing havingintake and discharge ports, a valve therein projecting through andpartially choking the intake port for permitting continuous How of aminimum volume of airI under pressure through said casing, a Huidpressure responsive, springheld element associated with said valve andnormally maintaining the same in said position against the pressure ofair passing the same and adapted, upon increase of ressure in the.casing due to obstruction o the discharge port, to move said valve tofully open the intake port, an air discharge tube, and a manuallyoperable normall open element interposed between said tube and thedischarge endv of said casing for permitting digital choking of saiddischarge port for effecting actuation of said valve. Y

2. An air feed device for ice plants including a valve-casing havingintake and discharge ports, a valve therein projecting through andpartially Vchoking the intake port for permitting continuous flow of aminimum volume of air under pressure through said casing, areciprocatory fluid pressure responsive spring-held element carryingsaid valve and normally maintaining the same in said position againstthe pressure of air passing the same and adapted, upon increase' ofpressure in the casing due to obstruction of the discharge port, to movesaid valve4 in the direction of' travel ofthe airI to fully open, theintake port, an air discharge tube, and a manually operable normallyopen element interposed between said tube and the discharge end ofsaidcasing for permitting digital choking of said discharge port foreffecting actuation of said valve.

3. A valve casing having an intake and a. discharge port, a spring-heldpiston in said casing carrying a valve` member normally positioned tomaintain said intake port partially open yfor the passage through saidcasing of a minimum volume of fluid under pressure, an air yexhaust portassociated with the piston to permit free response of the latter tofluid pressure against the action of said spring for effectingquick fullo ning of said intake port upon clogging of t e discharge port byaccumulation of fluid pressure within the casing to thereby effectblowing out of the obstruction in the discharge port, said valve memberprojecting into the intake port for veffecting cleansing thereof duringreciprocatory movements of said member. Y

4. A valve casing having an intake and a discharge port, a'spring-heldpiston in said casing carrying a valve member normally positioned tomaintain said intake port partially open for Vthe passage through saidcasing of a minimum volume of fluid under pressure, an air exhaust portassociated with the piston'to permit free response of the latter tofluid pressure against the action of said spring for effecting quickfull opening of saidintake port upon clogging of the discharge port byaccumulation of fluid pressure-within thecasing to thereby effectblowing out of the obstruction in the discharge port, said valve memberprojecting into the intake port and loosely associated with said pistonfor permitting limited lateral movement ofsaid valve member in cont-actwith the inner surface of the intake port for mainltaining thev latterfree of obst-ructions.

5f A valve casing having an intake port at one end andi a discharge portat its other end, the latter being always open, a fluid pressureresponsive member between the .ends of said casing, a valve membercarried loosely associated with said fluid pressure responsive memberand projecting into said intake port for movement therein when in normalposition for. maintaining said port free of obstructions. Y

l6. A valve casing having intake and discharge ports at opposite ends,the latter always fully open, afreely rotatable valve member normallypartially choking said intake port to permit constant flow of a minimumvolume Yof fluid under pressure through the said casing and maintainednormally in motion by inflowing air to maintain said intake port free ofobstruction, a spring-held fluid. pressure responsive element within thecasingl carrying said valve-member, a stop for said element againstwhich it is held by said spring, said element adapted to respond toincrease in normal pressure of fluid within saidcasing due to choking ofthe discharge 4 port to effect rapid full opening of said intake port topermit passage of a larger volume offluidunder pressure to free saiddischarge port Iof obstruction and thereupon return said valve member tonormal position. A 7. A valve casing having intake and discharge portsat opposite ends, the latter always fully open, Aa valve member normallypartially choking said intake port to Apermit constant flow of a minimumvolume of fluid under pressure through the said casing, a spring-held,fluid pressure responsive element within the casing having universaljoint connection with said valve member for permitting rotary movementof the latter under the influence of the flow of fluid past the same,said member projecting into the intake port and maintaining the latterfree of obstruction by said yrotary movement, a stop for said elementagainst which it is held by said spring, saidelementadapted to respondtoA increase in normal pressure of Huid within said casing'due toclicking of the discharge port to effect rapid full opening of4 saidVintake port to permit passage of a larger `vol ume of fluid underpressure to free said discharge portof obstruction and thereupon returnsaid valve member to normal position.

8. An air-supply valve including a casing havingan air inlet portbordered at one end by a valve-seat, a valve member having threadedengagement with said casing for adjustment relativelyto said seat andhaving an air discharge port, an aii by-pass duct through said valvemember communicating with said discharge port for continuous passage ofair when said valve is seated, a lat` erally movable member maintainedinmotion by the air passing through said intake port projecting into theintake end of said by-pass for partially'choking the same andmaintaining it fcleary of obstructions and a spring-held fluid pressureresponsive member pivotallyV associated with said member for withdrawingythe same from said intake end as the pressure within said casingincreases Vresponsively to choking or the discharge port.

9. An air-supply valve including a'casing having an air inlet portbordered at one end by a valve-seat, a valve member having threadedengagement with said casing for adjustment relatively to said seatandhaving an air discharge port, an air by-pass duct through said valvemember communicating with said discharge port for continuousl passage ofair whenV said valve is seated, a member maintained in motion by the airpassing throughsaid intake port longitudinally vand laterally movablerelatively to said valve member and projecting into the intake end ofsaid by-pass for at least partially choking the same and maintaining itfree of obstruction, a chamber in said casingV open at one end toatmosphere, and aV spring-held valve therein arranged to prevent leakagefrom said casing and operatively associated'with said member to withdrawthe same from said intake end as said valve moves responsively toincrease in pressure within thecasing due to choking` of thedischargeport.

10. A valve for `feeding a normal predetermined volume of fluid underpressure against back-pressure Which includes a casing having a passagetherethrough, a member adjustably mount-ed in said casing and havingapassage therethrough constituting a continuation of the passage throughsaid casing, a valve-seat at the discharge end of the latter, saidmember including a valve element seating on said valve-seat, aspringheld valve carriedby'sai'd member and normally partially chokingthe passage inthe latter, to thereby limit the passage of fluid throughthe said member When said. valve element is seated', the latter adaptedto be unseated to thereby effect by-passage of the fluid with respect tosaid spring-held valve.

l1. A valve for feeding a normal predetermined volume of fluid underpressure against a predetermined back-pressure which `includes a casinghaving a passage therethrough, a member adjustably mounted in saidcasing and having a passage therethrough constituting a continuation ofthe passage through said casing, a valve-seat at the discharge end ofthe latter, said member including a valve element seating on saidvalve-seat, a spring-held valve carried by said member and normallychoking the passage in the latter, at least in part, to thereby limitthe passage of fluid through the said member when said valve element isseated, thel latter adapted to be unseated to thereby effect by-passageof the fluid with respect to said spring-held valve, said spring-heldvalve loosely associated with said member to permit free lateralmovement thereof with respect to the portion of the passage chokedthereby to effect automatic cleansing of said portion of said passage.

l2. A discharge nozzle for fluid under pressure including a casinghaving a passage therethrough, there being a back-pressure chamberbetween the ends of said passage, a cylinder' communicating at one endwith atmosphere and at its other end with said chamber, a spring-heldpiston in said cylinder, a valve element carried thereby normallypositioned to partially choke said passage, the spring for said pistoncooperating with the inlet of air into said chamber and the normalback-pressure afforded by the discharge end of said passage to maintainsaid valve element in predetermined position so long as the dischargeend of said passage is free from other obstructive matter and continuesto discharge the normal volume of fluid, and automatically effecting areciprocatory movement of said piston and valve element upon increase ofback-pressure due to clogging of said discharge end of said passage inwhole or in part, to thereby effect ejection of the obstructive matter,said valve element having universal joint connection with said pistonand adapted to be maintained in motion by the fiuid passing the same tothereby maintain clean the said clicked portion of said passage.

13. A fluid supply valve including a cas'- ing having an air intake portbordered at one end by a valve-seat, a valve adjustable relatively tosaid seat, a main discharge port for air passing said valve, a by-passduct communicating with said discharge port and having its intake enddisposed to communicate with said intake port when said valve is seated,a valve controlling said by-pass duct for effecting normal delivery of avery minute volume of fluid from said discharge port, and fluid pressureactuated, springheld means associated with said by-pass valve forautomatically effecting full opening of said by-pass duct in event ofclogging of the discharge port for clearing the latter of obstructions.

14. An air supply valve including a casing comprising two partsrotatable relatively to each other, an air intake port in one of saidparts, an air' discharge port for the other of said parts, a valvecarried by the latter for controlling said intake port and adapted to bemoved toward and from the latter as said parts of said casing arerelatively rotated, an auxiliary intake port in said valve communicatingwith the intake port of the casing when said valve is seated, aspring-held fluid pressure responsive valve controlling said auxiliaryintake port for permitting constant flow of a minimum volume of airthrough said casing when said first named valve is seated and adapted toautomatically effect full opening of said auxiliary port upon increaseof normal pressure in said casing due to clogging of the discharge port.

l5. A device for maintaining a constant controlled flow of fluid underpressure against a substantially constant hydrostatic resistant whichcomprises a casing having an intake port for association with a sourceof fluid under pressure, a discharge port from said casing, a passagetherein between the intake and discharge ports communicating at one endwith atmosphere, a springheld reciprocable fiuid pressure responsivevalve in said casing shutting off the connection between the latter andatmosphere, a freely rotatable choke member pivotally associated withsaid valve and normally proj ecting into said discharge port, saidmember being maintained in motion by incoming fluid to maintain saidintake port free of' obstruction and being withdrawn from said port bysaid valve as the latter is moved responsively to increase in pressurein said casing due to increase of the normal resistant to discharge fromsaid casing, and a member in the latter manually adjustable to effectby-passage of fluid relatively to said intake port to increase the rateof discharge from said casing.

IRVING COWLES.

